Harrison M. Abrahams

Topiramate-induced nephrolithiasis

Topiramate is a recently developed antiepileptic medication that is becoming more widely prescribed because of its efficacy in treating refractory seizures. Urologists should be aware that this medication can cause metabolic acidosis in patients secondary to inhibition of carbonic anhydrase. In addition, a distal tubular acidification defect may result, thus impairing the normal compensatory drop in urine pH. These factors can lead to the development of calcium phosphate nephrolithiasis. We report the first two cases of topiramate-induced nephrolithiasis in the urologic literature.

Pure laparoscopic right donor nephrectomy : step-by-step approach

BACKGROUND AND PURPOSE Debate surrounds laparoscopic kidney procurement for right donor nephrectomy. We detail our pure laparoscopic technique of right kidney retrieval. TECHNIQUE We use a four-port transperitoneal approach and extract the kidney through a low Pfannenstiel incision. Important elements include: (1) dividing the triangular ligament; (2) identifying the vena cava early; (3) minimizing ureteral dissection; (4) mobilizing the kidney within Gerotas fascia; (5) dissecting the renal artery behind the vena cava; (6) cutting the extraction incision to the peritoneum; (7) applying a Hem-o-Lok and single metal clip on the artery; (8) placing the Endo-TA stapler on the renal vein adjacent to the vena cava; (9) cutting the vessels without clips/staples on the kidney side; and (10) retrieving the kidney manually. RESULTS AND CONCLUSIONS This is a reliable method of right pure laparoscopic donor nephrectomy that maximizes donor benefit and cost-effectiveness. Right laparoscopic nephrectomy is likely easier with this technique and should not be avoided if it is the preferred kidney for transplantation.

Simplified pure laparoscopic bowel anastomosis

Laparoscopic bowel anastomosis can be a challenging and time-consuming process. No detailed intracorporeal technique has been well described, and most laparoscopists use an extracorporeal technique, which has many disadvantages. We detail a simple, pure laparoscopic method that creates a capacious isoperistaltic side-to-side enteroenterostomy.

Laparoscopic radical nephrectomy: financial disincentives by the Health Care Financing Administration.

BACKGROUND AND PURPOSE Laparoscopic radical nephrectomy is a minimally invasive alternative to open radical nephrectomy. We have noticed that since the beginning of 2001, when the Current Procedural Terminology (CPT) code 50545 became available for laparoscopic nephrectomy, the reimbursement for the laparoscopic operation was significantly lowered. This led us to survey 25 laparoscopic urologic surgeons to assess trends in reimbursement from all over the United States. MATERIALS AND METHODS During this period, the records of reimbursements for radical nephrectomy were available from a single practice to compare that for the open and laparoscopic techniques. The 19 open and 10 laparoscopic operations were entered in a database for statistical analysis. Endourologists around the country also were polled on the subject. RESULTS The average reimbursement for an open radical nephrectomy was

Upper quadrant access for urologic laparoscopy.

1581 +/- 325 (SD), while the average reimbursement for a laparoscopic radical nephrectomy was

Endoscopic Management of Milk of Calcium-Filled Ureterocele Stump

1192 +/- 184. Twenty-five polled endourologists had noted similar reductions in reimbursement for laparoscopic procedures. Many of those polled had participated in the Specialty Society Relative Value Unit (RVU) survey for laparoscopic radical nephrectomy and stated that their recommendations were that the value be considered greater than that of the open counterpart. CONCLUSION The highly significant difference in reimbursement reflects a financial disincentive to surgeons performing laparoscopic procedures. It is obvious that in the U.S., the Health Care Financing Administration (now the Centers for Medicare and Medicaid Services) is devaluating all surgical procedures, and financial pressures of this type are disturbing.

Theories of Stone Formation

Initial access into the peritoneum and establishing pneumoperitoneum are required for laparoscopy. Various techniques have been described to achieve insufflation and place trocars. We describe our method of initial entry into the upper quadrant and subsequent incorporation of this site as a working port during upper urinary tract laparoscopy. This is an easy and safe means of entering the peritoneum, even after prior surgery, and provides a functional trocar for retraction and dissection.

Urinary Stone Inhibitors

A 38-year-old woman with a duplicated right collecting system and a history of right upper-pole heminephrectomy was referred for persistent dysuria and right lower-quadrant abdominal discomfort. Imaging identified a remnant ureter and a ureterocele filled with what appeared to be a large homogenous stone. At cystoscopy, the ureterocele was incised with a holmium:YAG laser, releasing a large quantity of white milky fluid (milk of calcium). There was no evidence of any solid material. Endoscopic evaluation should be the first step in patients with stones in a ureteral stump because milk of calcium may be the etiology of what appears to be a large stone burden in an obstructed system.

MP50-16 INITIAL CLINICAL EXPERIENCE WITH A SINGLE-USE DIGITAL FLEXIBLE URETEROSCOPE

Water is a pivotal element in digestion, circulation, elimination, and regulation of body temperature. A critical function of the urinary system is the maintenance of normal composition and volume of body fluid; this is accomplished by glomerular filtration, tubular reabsorption, and tubular secretion of soluble and filterable plasma components. By such means, urine contains water, electrolytes, minerals, hydrogen ions, end products of protein metabolism, and other compounds not useful to the metabolism, energy requirements, or structure of the body. Under normal circumstances, urine will not contain solid particles (stones).

The primary stone event: a new hypothesis involving a vascular etiology.

It is intriguing that despite marked abnormal urinary factors, most humans will not form stones. Alternatively, some patients develop stones despite normal urinary composition. The key element, therefore, appears to be inhibition of the steps in calculogenesis (nucleation, crystal growth, aggregation, and crystal/stone retention). Urolithiasis will not develop if any one of these steps is blocked. Despite this simple fact, it is unclear exactly why many people form stones. Numerous molecules have been identified that inhibit crystallization in vitro but many stone formers have normal levels of these substances; others will continue to develop stones despite replacement of these known inhibitors. The formation of urinary calculi requires a complex combination of factors, both promoting and inhibiting stone formation. Fortunately, there are many patients who can be helped because of our existing knowledge about two specific urinary inhibitors: citrate and magnesium. This chapter will discuss the in vitro and in vivo evidence regarding citrate and magnesium as inhibitors of urinary stone disease.